"What is a hobby anyway? Where is the line of demarcation between hobbies and ordinary normal pursuits? I have been unable to answer this question to my own satisfaction. At first blush I am tempted to conclude that a satisfactory hobby must be in large degree useless, inefficient, laborious, or irrelevant. Certainly many of our most satisfying avocations today consist of making something by hand which machines can usually make more quickly and cheaply, and sometimes better. Nevertheless I must in fairness admit that in a different age the mere fashioning of a machine might have been an excellent hobby… Today the invention of a new machine, however noteworthy to industry, would, as a hobby, be trite stuff. Perhaps we have here the real inwardness of our own question: A hobby is a defiance of the contemporary. It is an assertion of those permanent values which the momentary eddies of social evolution have contravened or overlooked. If this is true, then we may also say that every hobbyist is inherently a radical, and that his tribe is inherently a minority.
This, however, is serious: Becoming serious is a grievous fault in hobbyists. It is an axiom that no hobby should either seek or need rational justification. To wish to do it is reason enough. To find reasons why it is useful or beneficial converts it at once from an avocation into an industry–lowers it at once to the ignominious category of an ‘exercise’ undertaken for health, power, or profit. Lifting dumbbells is not a hobby. It is a confession of subservience, not an assertion of liberty.”
— Aldo Leopold (A Sand County Almanac)